A wearable fitness and health-tracking device, paired with a subscription app, that continuously monitors metrics like heart rate, sleep, and strain to give users personalized recovery and performance guidance.
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Sharp valuation acceleration ($3.6B in 2021 to $10.1B in March 2026), driven by continued wearables/health-data momentum and a marquee athlete/celebrity investor roster (Cristiano Ronaldo, LeBron James, Rory McIlroy, and others) that also functions as a distribution asset. The Series G-2 tranche is a SAFE-to-preferred conversion (confirmed via a SuRo Capital Corp. SEC filing), not a separately-led round. CEO Will Ahmed said at the March 2026 Series G close that it is expected to be WHOOP's 'last private round of financing' with an IPO as the 'next step'; a later (Aug 2026) Bloomberg interview reportedly has him targeting roughly 18 months out, tied to a Boston HQ expansion and 600-person hiring plan. No S-1 or confidential filing exists yet, unlike wearables peers Oura and Strava, which filed confidentially in 2026.
Low: Revelio Labs, Mar 2026. High: Tracxn, Aug 2026.
As of 2026-09-13 · live via ashby's public job board · ≈10.8% of the 1,200–1,650 estimated team
+41 more roles across 16 other teams.
See all open roles at WHOOP →WHOOP makes a screenless wrist strap that measures heart rate continuously by optical sensing alongside an accelerometer, and turns overnight readings into proprietary Recovery, Strain and Sleep scores. Newer hardware adds an ECG electrode with FDA-cleared atrial-fibrillation detection and overnight blood-pressure estimates, a feature that drew an FDA warning letter and later a closeout letter.
| Date | Type | What |
|---|---|---|
| Jun 17, 2026 | Milestone | FDA closeout letter says it does not intend to enforce device requirements for Blood Pressure Insights as modified |
| Mar 2026 | Milestone | Most recent patent grant, on sleep-intention detection, issued |
| Jul 14, 2025 | Milestone | FDA warning letter says Blood Pressure Insights is a medical device lacking premarket approval and a 510(k), rejecting the general-wellness position |
| May 8, 2025 | Milestone | WHOOP 5.0 and WHOOP MG announced; MG adds an ECG electrode with FDA-cleared atrial-fibrillation detection and Blood Pressure Insights |
| 2025 | Paper | Inter- and Intrapersonal Associations Between Physiology and Mental Health: A Longitudinal Study Using Wearables and Mental Health Surveys |
| 2025 | Paper | Accurate comparison of wearables requires contextual equivalence |
| Nov 30, 2023 | Acquisition | AnyQuestion |
| Sep 26, 2023 | Milestone | WHOOP Coach, a chat feature built on OpenAI's GPT-4 over the member's data, launched |
| 2023 | Paper | Wearable derived cardiovascular responses to stressors in free-living conditions |
| Sep 8, 2021 | Milestone | WHOOP 4.0 announced with five LEDs, four photodiodes, a pulse oximeter and a skin-temperature sensor; the company described it as 33% smaller |
| Sep 2, 2021 | Acquisition | PUSH |
| 2021 | Milestone | Bellenger et al. (Sensors) find WHOOP 2.0 heart rate within 0.39% and lnRMSSD within 1.66% of ECG |
| 2021 | Paper | Changes in health promoting behavior during COVID-19 physical distancing: Utilizing wearable technology to examine trends in sleep, activity, and cardiovascular indicators of health |
| 2020 | Milestone | Patent granted for an optical front end that steps LED brightness and detector gain (US 10,750,958); a measurement-quality patent followed in 2021 |
| 2020 | Milestone | Miller et al. (Journal of Sports Sciences) compare WHOOP with polysomnography over 86 sleeps in 12 adults: 89% sleep/wake agreement (kappa 0.49) |
| 2020 | Paper | Analyzing changes in respiratory rate to predict the risk of COVID-19 infection |
| Oct 17, 2017 | Patent filed | US 11,185,292 Applied data quality metrics for physiological measurements |
| 2017 | Milestone | US 9,750,415 granted, covering heart-rate variability computed in the last phase of deep sleep before waking |
| Sep 15, 2016 | Patent filed | US 10,750,958 Variable brightness and gain for optimizing signal acquisition |
| Mar 5, 2014 | Patent filed | US 11,185,241 Continuous heart rate monitoring and interpretation |
| Sep 4, 2012 | Patent filed | US 9,750,415 Heart rate variability with sleep detection |
| Sep 4, 2012 | Patent filed | US 10,264,982 Physiological measurement system with motion sensing |
| 2012 | Milestone | Founded in Boston; the earliest patent family (priority September 4, 2012) describes tracking sleep and heart rate together to compute HRV |
Patents. The listed patents include computing heart-rate variability during sleep, an optical front end that steps LED brightness and detector gain, and a method for scoring the quality of each physiological measurement.
WHOOP, founded in Boston in 2012, builds a screenless wrist strap that measures heart rate continuously by photoplethysmography alongside an accelerometer. Its earliest patent family (priority September 4, 2012) describes tracking sleep and heart rate together to compute heart-rate variability in the last phase of deep sleep before waking (US 9,750,415, granted 2017). Later grants cover an optical front end that steps LED brightness and detector gain through discrete operating states (US 10,750,958, 2020) and a method for scoring the quality of each physiological measurement (US 11,185,292, 2021). The Recovery, Strain and Sleep scores in the app are derived from these overnight HRV, resting heart rate, respiratory rate and sleep-stage estimates; the scoring algorithms are proprietary and unpublished.
WHOOP 4.0, announced September 8, 2021, was described by the company as 33% smaller than the 3.0; it moved to five LEDs (three green, one red, one infrared) and four photodiodes, added a pulse oximeter and skin-temperature sensor, and shipped with a location-detection algorithm so the module could be worn in garments; WIRED reported the algorithm was trained on beta-tester data against chest straps and that the methodology was unpublished. WHOOP Coach, a chat feature built on OpenAI's GPT-4 over the member's data, launched September 26, 2023. WHOOP 5.0 and WHOOP MG, were announced May 8, 2025; the company states they are 7% smaller again, that the sensors sample about 26 times per second and that the battery lasts 14 days. The MG variant adds an ECG electrode in the clasp with an FDA-cleared atrial-fibrillation detection feature, and a Blood Pressure Insights feature that produces overnight estimated systolic and diastolic ranges from the optical signal after calibration against a cuff reading.
On July 14, 2025 the FDA issued a warning letter stating that Blood Pressure Insights is a medical device under section 201(h) of the FD&C Act because blood-pressure estimates are "inherently associated with the diagnosis of hypo- and hypertension", that the product was adulterated for lack of premarket approval and misbranded for lack of a 510(k), and rejecting WHOOP's position that it qualified for the general-wellness exemption. In a closeout letter dated June 17, 2026 the FDA said that, based on changes WHOOP made to the product and its labelling, it does not intend to enforce device requirements for Blood Pressure Insights as modified, citing its general-wellness guidance as updated January 6, 2026.
Independent validation consists of small laboratory studies. Miller et al. (Journal of Sports Sciences, 2020) compared WHOOP against polysomnography over 86 sleeps in 12 adults: two-stage sleep/wake agreement was 89% (kappa 0.49). Bellenger et al. (Sensors, 2021) found WHOOP 2.0 heart rate within 0.39% and lnRMSSD within 1.66% of ECG. WHOOP's own data-science staff have published analyses of aggregate member data in PLOS ONE (2020, 2021, 2023) and JMIR (2025). Google Patents lists about 23 US patents and applications assigned to Whoop Inc, including design patents; the most recent grant, on sleep-intention detection, issued in March 2026. WHOOP has made two acquisitions, both for undisclosed sums: PUSH, a Toronto maker of velocity-based-training sensors (September 2021), and AnyQuestion, a Boston AI question-and-answer content startup (November 2023).
Profile as of Sep 18, 2026.
| Round | Date | Valuation | Lead |
|---|---|---|---|
| Series G | 2026-03-31 | $10.1B+38% | Collaborative Fund |
| Series G-2 | 2026-03-30 | $7.3B+103% | Not applicable -- a SAFE-to-preferred conversion event, not an institutionally-led round (confirmed via a SuRo Capital Corp. SEC filing showing its WHOOP SAFE note converting to Series G-2 preferred on Feb 26 2026) |
| Series F | 2021-08-01 | $3.6B+200% | SoftBank Vision Fund 2 |
| Series E | 2020-10-01 | $1.2B | IVP |
| Undisclosed round (SEC Form D) | 2019-10-28 | — | Not disclosed -- SEC Form D lists only the company's own officers/directors, not the investor(s) |
| Undisclosed round (SEC Form D) | 2018-02-21 | — | Not disclosed -- SEC Form D lists only the company's own officers/directors, not the investor(s) |
| Undisclosed round (SEC Form D) | 2015-09-09 | — | Not disclosed -- SEC Form D lists only the company's own officers/directors, not the investor(s) |
| Undisclosed round (SEC Form D) | 2015-09-09 | — | Not disclosed -- SEC Form D lists only the company's own officers/directors, not the investor(s) |
| Undisclosed round (SEC Form D) | 2014-06-05 | — | Not disclosed -- SEC Form D lists only the company's own officers/directors, not the investor(s) |
| Undisclosed round (SEC Form D) | 2013-07-18 | — | Not disclosed -- SEC Form D lists only the company's own officers/directors, not the investor(s) |
No upcoming rounds currently reported.
| Status | S-1 Not Filed |
|---|---|
| Kalshi | Under 50% odds through Jan 1, 2028 (as of Sep 13, 2026 · market) |
| Timing | ~18 months from Aug 2026 (~early 2028, secondhand-sourced) |
| Notes | CEO Will Ahmed: Series G is expected to be WHOOP's 'last private round of financing... our next step is an IPO.' Grouped by trade press with Oura and Strava as part of a 2026 wearables IPO wave, though WHOOP is the only one of the three without a filing. |
| Source | Yahoo Finance / TechCrunch, Mar 31 2026; Bloomberg (via Boston Globe/TipRanks), Aug 12 2026 |
Polymarket/Kalshi rows are live market-implied odds, not a PrePost prediction; everything else is a cited news signal. PrePost doesn't publish its own IPO forecast.